Backward running (BR) is employed for conditioning and for rehabilitation in sports, orthopaedics, and neurology. Our purposes were to compare kinematics and training effects of BR to forward running (FR). Ten runners (6 males, 4 females, ages 20-34 years) were assigned to a backward running (BRG) or control (FRG) group. Subject isokinetic muscular torque production (IMTP) and biomechanics during FR and BR at 3.58 m/sec were studied at the beginning and after 8 weeks of training. Stance time was significantly shorter during BR. The peak vertical component of the ground reaction force (Fz) and Fz impulse were significantly less during BR. After training, knee extensor IMTP of the BRG increased significantly at 75 and 120°/sec. We concluded that BR produced lower Fz stress than FR and improved knee extensor torque at low speeds. Backward running may be clinically useful for reducing stress to injured joints and for increasing knee extensor strength.

J Orthop Sports Phys Ther 1989;11(2):56-63.

Study Design: Repeated-measures experiment. Objective: To compare measures of end point accuracy (EPA) for 2 feedback conditions: (1) visual and kinesthetic feedback and (2) kinesthetic feedback alone, during shoulder movements, at 3 different speeds. Background: Shoulder joint kinesthesia is typically reported with EPA measures, such as constant error. Reporting multiple measures of EPA, such as variable error and absolute error, could provide a more detailed description of performance. Methods and Measures: Subjects were seated with the shoulder abducted 90° in the scapular plane and externally rotated 75°, with the forearm placed in a custom shoulder wheel. Subjects internally rotated the shoulder 27° to a target position at 48° of shoulder external rotation for both conditions. Motion analysis was used to determine peak angular velocity and 3 EPA measures for shoulder movements. Each EPA measure was compared between the 2 feedback conditions and among the 3 speeds with a separate 2-way analysis of variance. Results: Movements performed with kinesthetic feedback alone, measured by constant error (P<.01), variable error (P<.01), and absolute error (P<.01), were less accurate than movements performed with visual and kinesthetic feedback. Faster movements were less accurate when measured by constant error (P = .01) and absolute error (P<.01) than slower movements. Subjects tended to overshoot the target in the absence of visual feedback; however, movement speed played minimal role in the overshooting. Conclusions: Multiple measures of EPA, such as constant, variable, and absolute error during simple restricted shoulder movements may provide additional information regarding the evaluation of a motor performance or identify different central nervous system control mechanisms for joint kinesthesia.

J Orthop Sports Phys Ther. 2004;34(8):468-478. doi:10.2519/jospt.2004.1151 

Key Words: kinesthesia, proprioception, target accuracy, upper extremity

This study attempted to determine the effect of eccentric quadriceps femoris, hamstring, and placebo fatigue on stance limb dynamics during the plant-and-cut phase of a crossover cut. Twenty female college students (task trained) were tested. Hamstring fatigue resulted in decreased peak impact knee flexion moments (p = .01), increased internal tibial rotation at peak knee flexion (p = .05), and decreased peak ankle dorsiflexion (p = .05). Quadriceps fatigue resulted in increased peak ankle dorsiflexion moments (p < .01), decreased peak posterior braking forces (p = .01), decreased peak knee extension moments (p = .01), delayed peak knee flexion (p = .01), delayed peak propulsive forces (p < .01), and delayed subtalar peak inversion moments (p = .05). Fatigue of either muscle group produced earlier peak ankle plantar flexion moments (p = .05) and decreased peak propulsive knee flexion moments (p = .05). Variables requiring further study (p = .1) provide discussion data. Soleus, gastrocnemius, tibialis anterior, and deep posterior compartment calf muscles serve as dynamic impact force attenuators, compensating for fatigued proximal muscles.

J Orthop Sports Phys Ther. 1997;25(3):171-184.

Key Words: women, muscle, fatigue, compensatory dynamics

Clinical assessment of the patellofemoral alignment is frequently performed, yet the repeatability of these measurements has not been previously investigated. This study examined the reliability of measuring patellofemoral alignment. The Q angle, A angle, and patellar orientation (mediolateral tilt, mediolateral position, superoinferior tilt, and rotation) of 27 healthy subjects were measured over 3 trials using standardized positioning and operationally defined goniometric, pluri-cal caliper, and visual estimation measurement techniques. Intratester and intertester intraclass correlation coefficients of measurements obtained with the pluri-cal caliper and goniometer ranged from .52 to .86 and .003 to .61, respectively. Intratester and intertester standard errors of the instrumented measurements ranged from 1.6° to 3.5° and 3.2° to 6.8° (.28 and .55 cm for mediolateral position), respectively. Intratester kappas of visually estimating patellar orientation ranged from .40 to .57. Intertester kappas were between .03 and .30. The results suggest that both clinical estimation and instrumented measurement of patellofemoral alignment may be unreliable.

J Orthop Sports Phys Ther. 1996;23(3):200-208.

Key Words: reliability, patellofemoral, alignment

Fatigue may be related to lower extremity injury. The effect of lower extremity fatigue on ground reaction force production, lower extremity kinematics, and muscle activation during the landing phase of a run and rapid stop was investigated. Subjects were 19 female, Division 1 collegiate basketball and volleyball players (x¯ age = 20.8 ± 1.8 years, x¯ weight = 71.7 ± 6.9 kg, x¯ height = 174 ± 5 cm). Dominant leg ground reaction and muscle activation data were sampled at 2,000 Hz. Lower extremity kinematic data were sampled at 200 Hz, and 3-dimensional analysis was performed. Knee extensor/flexor muscle activation tended to be delayed during fatigue (p=.08). Maximum knee flexion tended to occur earlier during fatigue (p=.09). Step-wise multiple regression suggested that the knee may be the primary site of force attenuation following fatigue. During fatigue, biodynamical compensations in the mechanical properties of the knee extensor musculature, as evidenced by differences in knee kinematics and muscle activation times, may occur to enhance knee stability.

J Orthop Sports Phys Ther. 1994;20(3):132-137.

Key Words: run and rapid stop, muscle action, biodynamics